Removable-bridge attachment.



C. NISHI.

REMOVABLE BRIDGE ATTACHMENT.

APPLICATION FILED MAR. 27. I916.

1,28,555, Patented Dec. 24, 1918.

INVENTOR.

E WITNESS 5 C. WISH] W/Z: I

H/fi A TTOR NE Y5.

CHOTGKU HISHI, 62 SAN FRANCISCO, CALIFORNIA.

REMOVABLE-BRIDGE ATTACHMENT.

specification of Letters Patent.

Patented Dec. 24 1918.

Application filed March 27. 1916. Serial No. 86,948.

To (ZZZ whom it may concern.

Be it known that I. Unorono lirsnr, a subject of Japan, and a resident of the city and county of San Francisco, State of California, have invented a certain new and useful Removable-Bridge Attachment, of .vhich the following is a. specification.

The invention relates to dentistry and particularly to means for attaching removable bridges in place in the mouth.

An ObJOCi; of the invention is to provide a removable bridge attachment, which permits the removal of the bridge without subjecting the abutments to strains."

Another object of the invention is to provide a. removable bridge attachment which will permit the bridge toadjust itself to new positions as the size or contour of the gums varies.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where I shall outline in full that form of the invention which I have selected for illustration in the drawings accompanying and forming part of the present specification. In the drawings 1 have shown only one specific form of my generic invention but it is to be understood that I do not limit myself to such form because my invention may be embodied in a multiplicity of forms, each being a species ofmy said invention. It is also to be understood that by the claims succeeding the description of my invention, I desire to cover the invention in whatever form it may be embodied.

Referring to said drawings:

Figure 1 is a plan view of an upper jaw, showing one form of removable bridge arranged thereon.

Fig. 2 is a plan view of the same jaw, with the bridge removed.

Fig. 3 is a side view of the abutment and lug.

Fig. 4 is a side view of one side of the bridge showing the attachment of my invention arranged vertically therein.

Fig. 5 is an underneath view of the other side of the bridge showing the attachment arranged horizontally.

Fig. 6 is a perspective view of the horizontal attachment on an enlarged scale.

Fig. 7 is a perspective view of the vertical attachment on an enlarged scale.

Fig. 8 is a view of the face of the attachment on an enlarged scale.

Removable bridges are very widely used in dentistry and their advantages and the necessity for their use are so well known that a statement thereof is not necessaryhere. These bridges are usually held in place by lugs 2 secured to the tooth or tooth roots at one or both ends of the bridge and these lugs are usually secured to abutments or crowns 3, covering the teeth or roots at one or both ends of the bridge. These lugs project outward from the abutments and overlie the gums and must be parallel to each other in order that the bridge may be placed or removed. These lugs are usually broadened at their outer ends and heretofore have usually been T-shaped in cross section. It is essential that the bridge be held rather securely in position so that it will not become dislodged during mastication or other processes. Heretofore, the bridge has been provided with sockets in which the lugs are disposed when the bridge is in place and the lugs fitted tightly in the sockets and bottomed therein. This construction causes the masticating strains to be carried by the lugs and hence by the crowned teeth or roots and as a consequence, the abutments were often quickly loosened. When first fitted, the bridge plates were made to contact with the gums, but the gums shrink and change their conformation and then the entire strain is carried by the abutments. Also, when removing the bridge, it is almost essential to loosen one attachment at a time, and on account of the close fit of abutment and socket, the leverage or tipping strain is thrown on the other abutment causing it to be eventually loosened,

In accordance. with my invention these various deleterious features are overcome by the provision of a resilient connection between the bridge and the abutment. This arrangement operates to hold the bridge firmly in place, permits it to move against the gum ridges as the gums shrink and also permits the removal of the bridge without subjecting the abutments to serious strains.

The attachment of my invention comprises a case 4, preferably made of gold or gold alloy, which is soldered to or vulcanized into the bridge during its preparation. The case is formed with a somewhat circular body and is provided with a rolled or overturned edge 5. Arranged in the body and seating under the overturned edge 5 is a spring 6, of clasp gold, gold or platinum alloy or other suitable material. The spring is inserted in the case after the case has been secured to the bridge, hence the spring is not heated or impaired and is in perfect condi tion. The spring is shaped to engage the sides of the lug and When the bridge is in place causes the bridge to be securely held. The case is provided with a pocket into which the lug extends when the bridge is in place. The cases are made in tWo shapes, one to be placed horizontally and the other vertically and these two shapes are advisable on account of the difierent conditions met With in dentistry. The horizontal attachment is used principally for close bites and ment.

the vertical attachment for close bites and also between cuspid and cuspid. In Figs. 4c and '4 I have shown the vertical'attachment and in Figs. 5 and 6 the horizontal attach- 4 The pocket into Whichthe lug extends lies substantially vertical and in the vertical attachment, 'thepocket 7 lies sub- 1 stantially parallel to the body of the case,

Whereas in the horizontal attachment, the

' pocket 8 lies substantiallyperpendicular to that the masticating strains are. placed on Copies of this patent may be obtained for the gum ridges and not on the abutments- In Fig. 1 I have shoWn one particular form of removable bridge, but it is to be understood that I do not limit myself to any form.

I claim:

1. An attachment for removable bridges comprising a casing adapted to be attached to the bridge, and having a seat therein, a

flange on said casing, a spring seating against said flange and partly overlying said seat and adapted to frictionally engage on opposite sides of a fixed lug and a fixed lug adapted to be secured to a tooth and to extend into said seat. 7

2. An attachment for removable bridges, comprising a circular casing adapted to be attached to the bridge and having a seat therein, an overhangingmarginal flange on said casing, a tortuously bent spring seating five cents each, by addressing the Commissionerof Patents,

Washington, D. G. 

